Centerless grinding machine



March 30, 1954 H CENTERLESS GRINDING MACHINE l6 Sheets-Sheet 1' Original Filed April 15, 1949 lNVENTOR O/VA E. H/u

Y%IM ATToRNEy March 30, 1954 o. E. HILL CENTERLESS GRINDING MACHINE;

16 Sheets-Sheet 2 Original Filed April 15, 1949 INVENTOR OH/A EH/u Fig; 2

March 30, 1954 0, L Re. 23,808

CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Sheets-Sheet 3 INVENTOR O/l/A E. H/LL March 30, 1954 HILL Re. 23,808 CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Shets-Shet 4 INVE NTOR 0mm 5. H/LL y ATTORNEV March 30, 1954 o. E. HILL R 23,808

CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Sheets-Sheet 5 I Fig. 7

I'NVENTOR O/VA EH/LL 94-FG-7 ATTORNEy March 30, 1954 o. E. HILL Re. 23,

CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 l6 Sheets-Sheet 6 2.29 1 g 3 r O Q 212 I g I 68 i I D) i i I I z? v 4/ El? 2% &24 22a 222 a.

use 18 I95- INvENToR O/vA EH/LL Fig. 3

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CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Sheets-Sheet 9 r Fig. 17

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CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 l6 Sheets-Sheet 12 Fig. 22

INVE NTOR ATTORNEY March 30, 1954 0, 7 Re. 23,808

CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 l6 Sheets-Sheet 15 INVENTO R y @YFQBV;

5 5 ATToRNEy March 30, 1954 CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 O. E. HILL 16 Sheets-Sheet 14 IOBO INVENTO R ATTOR NEy March 30, 1954 0. E. HILL Re. 23,808

CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Sheets-Sheet 15 INVENTOR ATTOR Ey March HILL CENTERLESS GRINDING MACHINE Original Filed April 15, 1949 16 Sheets-Sheet 16 IZDI TRUE INVENTOR O/vA E. HILL f: ATTOR Ey Reiseued Mar. 30, 1954 Massachusetts oan'rsamss GRINDING. I

om E. mu, Worcester, Mass., wins. amt-s Company, Worcester, Mala, a

corporation of Original No. 2,597,242, dated May 20, 1952, Serial No. 87,720, April 15, 1949. Application for reissue January 29, 195.4, Serial No. 407,190

'. 3s cam to], 51-103)- Matter enclosed in heavy brackets fl appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

The invention relates to centerless grinders. This application is a continuation in part of my copending application Serial No. 45,388, filed August 20, 1948, and now abandoned.

One object of the invention is.to provide a superior centerless grinder for grinding tapered workpieces. Another object of the invention is to provide .a superior centerless grinder for grinding shouldered workpieces. Another object of the invention is to provide a superior centerless grinder which can be used for through feed grinding and for inieed grinding and which can be quickly converted from one to the other condition. Another object of the invention is to provide a centerless grinder for grinding shouldered work which is economical of the grinding wheel. Another object of the invention is to provide a centerless grinder particularly immune to vibration hence capable of producing not only accurate but also very regular and smooth workpieces. Another object of. the invention is to provide a centerless grinder with compensating mechanism for resetting the machine after truing of the grinding wheel thus to avoid errors by failure .to reset'manually and to lighten the burden on the operator.

Another object of the invention is .to provide a centerless grinder with all the adJustments commonly needed and so organized and arranged as to reducedifficulties in making relative ad- Justments. to provide a truly precision centerless grinder which is easy to operate and adjust. Another object of the invention is to provide a centerless grinder with a delicate infeed mechanism which slows down infeed as the work comes to size thereby enabling pieces to be ground to very close tolerances and giving smooth finishes. Another ob ect of the invention is to provide a hydraulically actuated centerless grinder of one or more of the above characteristics.

Another object of the invention is to provide a simple and dependable drive for the regulating wheel capable of rotating the regulating wheel at a wide range of speeds for grinding at various work speeds and also for truing the regulating wheel. Another object of the invention is to provide a centerless grinder which changes the R. P. M. of the workpiece during a given grinding operation, this feature being either alone or in combination with slow down of the infeed during said grinding operation. Another object of the invention is to provide an infeed centerless grinder capable of reducing the work to the required tolerances and capableof giving the work the required finish in a single operation by the machine or in a few number of op- Another object of the invention is Y erations by the machine. Another object of the invention is to provide a machine of the above character and having one or more of the above features which is rugged and highly dependable in practical operation. Another object of the invention is to provide a machine of the character indicated which can be embodied in an automatic, semi-automatic or manually operated machine.

Another object of the invention is to provide a centerless grinder which can be quickly changed over from a hand operated machine to a semiautomatic or automatic machine, that 'is to say to do infeed grinding by hand if desired, or to complete one grinding operation after the operator has started it, or to perform a selected number of infeed grinding operations followed by automatic truing and compensating followed by more grinding operations and so on, or to cause the wheel slide to move in and out to perform complete grinding operations continuously without interruption. Another object of the invention is to provide a dwell for sparking out if desired. Another object of the invention is to provide a centerless grinder for grinding shouldered work which is economical of the grinding wheel.

Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, all as will be exemplifled in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Figure 1 is a front elevation of a centerless grinder constructed according to the invention.

Figure 2 is an elevation of the left hand side of the grinder.

Figure 3 is an elevation of the right hand side of the grinder.

Figure 4 is a vertical sectional view of the feeding mechanism.

Figure 5 is a sectional view of the feeding mechanism, the upper portion of this figure showing a horizontal section, and the lower portion showing a vertical section.

Figure 6 is a front elevation of the handwheel and .controls for adjusting the position of the grinding wheel. 1

Figure 'l is a vertical sectional view of the feed screw shaft showing a. worm drive to rotate it when the compensating mechanism operates.

Fi ure 8 is a. horizontal axial sectional view of the regulating wheel and housing therefor, the housing being adjustable to various skew angles, showing 'also a fluid motor and driving connections to rotate the regulating wheel at various speeds.

Figure 9 is a. plan view of the truing mechanism for the regulating wheel.

Figure 10 is a front elevation of the truing mechanism for the regulating wheel.

Figure 11 is a vertical sectional view of the timin mechanism for the regulating wheel.

Figure 12 is a vertical axial sectional view of the truing post mounting of the truing mechanism for the regulating wheel. 1;

Figure 13 is a vertical axial sectional view of the grinding wheel spindle journals and reciprocator.

Figure 14 is a plan view of the spindle and reciprocator.

Figure 15 is a. side elevation of the work rest and elector. i

Figure 16 is a vertical axial sectional view of th twins post of the truing mechanism for the grinding wheel and also showing the wheel guard in section and many parts in elevation.

Figure 17 is a horizontal sectional view of this truing post taken on the line ll-il of Figure i6, and also showing many parts in plan;

Figure 18 is a horizontal sectional view of the cylinder and through the truing post of the truing mechanism for the grinding wheel.

Figure 19 is a vertical sectional view of the mechanism for moving the truing post and for compensating feeding of the grinding wheel;

Figure 20 is a plan view of the ratchet mechanism of the compensator drive.

Figure 21 is a sectional view of the piston cylinder and valve mechanism of the compensator drive.

Figures 22 and 23 are diagrams of the hydraulic mechanism and connections.

Figure 24 is a wiring diagram.

Figure 25 is a diagram of the hydraulic mechanism and connections similar to Figure 22 but illustrating a modification of the invention.

Figure 26 is a wiring'diagram similar to Figure 24 but illustrating saidmodiflcation of the invention.

Referring first to Figures 1, 2 and 3, the machine has a massive base III the inside of which is formed to provide a pair of tanks II and 22 respectively for hydraulic fluid (preferably oil) and coolant, which may be water with a grinding compound. If desired, apparatus for cooling and lubrication of grinding may be embodied in a system wherein one liquid is used for cooling and another liquid is used to lubricate the grinding action, these liquids being separately directed to the workpiece and the grinding wheel all in accordance with the disclosure of U. 8. Letters Patent No. 2,434,679 to Warner and Wickstrom. However in this embodiment only a single tank 22 and a single pump 23 for pumping liquid through a, pipe 24 is illustrated. The pipe 24 goes to a selector valve '25 which is connected to a nozzle 28 to direct cooling and lubricating fluid onto the workpiece W and the valve II is also connected to a pipe 21 which leads to a train:

is controlled by a handle ll which 13 e used to shut off the valve or to direct the fluid into the nozzle 28 or to direct the fluid into the pipe 21.

Referring now to Figure 2, on top of the base 20 at the left hand side of the machine is rigidly secured a wheel slide base 35 having a flat way 36 and a v way 31. Upon these ways 36 and 31 is mounted a massive grinding wheel slide 38 having a flat way 39 to engage the flat way 36 and having a v way 40 to engage the V way 31. This wheel slide can be moved either manually or automatically to the right or to the left as viewed from the front of the machine in a manner and by mechanism to be hereinafter described. Mounted upon the wheel slide 38 and adjustable in th same direction as the wheel slide moves is a motor table ll to which is fastened a large electric motor I! driving a shaft 43 upon which as better shown in Figure l is a multiple V pulley ll driving V belts 45 which go to a pulley 46 on the spindle 41 to which is fastened the grinding wheel ill. The belts 45 are enclosed in a casing ii.

Referring now to Figure 3, on th righthand side of the machine which this figure illustrates the base 20 has a flat top 55 supportin a swivel table 58. Referring now to Figure 1, this swivel table 56 swivels on a pin I1 rigidly secured to the base 20. Referring again to Figure 3, the swivel table 56 has a dovetailed slideway so supporting a slide BI. Referring-to Figures 1, 3 and 8, extending upwardly from the slide ii is a standard 62 the upper end 63 of which is drilled and tapped to form a nut. Passing through the nut 63 is a screw shaft 84 which is journalled in thrust'bearings in a round plate 58 which is attached by means of bolts 61 to a large support 68 extending upwardly from and secured to the swivel table 56. This support 63 and also the plate 66 hold a regulating wheel housing 69 in any desired position of skew angle adjustment. the axis of adjustment being horizontal and parallel to the front of the machine. In the housing 6! and journalled on an axis perpendicular to the axis of skew adjustment is the regulating wheel Ill. Any suitable means may be provided for securing the swivel table 56 to the flat top 55 after the desired angular adjustment has been made. For example, as shown in Figure 3, a plurality of bolts Il may extend through the swivel table 56 into tapped holes in the flat top 55 of the base 20, these bolts H passing through arcuate slots, not shown, in the swivel table 56.

Referring now to Figure 4, depending from the wheel slide 33 is a nut support I! having secured thereto by means of bolts 18 a nut housing 11. This nut housing ll journals, by means of ball bearings I8, a combination nut and worm wheel Ill through which extends a screw shaft 8|. The screw shaft 3| extends through and is keyed to a sleeve 82 at the right hand side, Figure 4, and extends through and is keyed to a. sleeve 33 at the left hand side. The sleeve 83 has formed integrally therewith a bevelgear 84. The sleeve 82 is iournalled in a ball bearing journal 85 which is supported by the wheel slide bas 35 and likewise the sleeve 83 is journalled in a ball bearing Journal 38 which is also supported by the wheel slide base ll. The screw shaft 3| is free to move axially in the sleeves II and ll a limited distance.

Referring now to Figure 5, extending from the front wall of the base II to the wheel slide base 35 is a shaft ll. Pinned to this shaft by means of a pin it is a short shaft which is iournalled in a ball bearing assembly as located in a housing as secured to the wheel slide base To the far end of the short shaft 02 is secured a bevel gear 80 which meshes with the bevel gear 00; Thus whenever the shaft, 90 is turned the screw shaft II is turned thereby mov--- ingthewheelslide II. a d Any suitable-hand operated mechanism may be provided on the front of.the machine for manually actuating the shaft 00. In Figures 5 and 6, I have shown a delicate manual actuator.

A hand wheel I00 having a handle I0! is freely iournalled on a stud I02 which has an integral disc portion I03 permitting it to be rigidly boltedto'a plate Illxwhich is secured to pads I00 formed on the front of the base 20. 'Journalled on another portion-of the stud I02 is a gear I00- which has a long hub I01 with a gear Mai smaller than the gear I00. The latter meshes withagear I08 which is secured to the frontend of the shaft on. The shaft In. is joumalle'd in aball bearing II I mounted in the plate :I0'4. A cover,

on at the front of'the machine a knob Ill and having pinion gear teeth I10 out thereon at the other end. The pinion teeth IIB mesh with the gear I00. The pinion teeth Ilficaxf, however, be

pulled out of mesh with the gear I08 by pulling the knob Ill. A spring IIG normally holds the pinion teeth III in engagement with the gear I00. This is a delicate feed mechanism whereby. turning of the knob II! will give slight increments of feed and it is also a fast operating hand feed mechanism operated by turning the hand wheel I00.

Referring to Figure 6, the hand wheel I00 has a stop I which will engage a stop arm I2I mounted on a pin I22 secured to the base 20. This stop-arm I2I can be pulled out of the way by means ofa finger portion I23 whenever desired. This combination of devices is useful for recording the previous position of the wheel slide as will be readily understood by those familiar with grinding machines generally.

Referring now to Figure 7, meshing with the worm wheel part of the nut and worm wheel 80 is a worm I20 secured to the reduced end portion I20 of a vertical shaft I21. This reduced end portion I28 is journalled in a pair of ball bearings I 20 mounted in a portion of the nut housing 11. Whenever the shaft I21 is turned, the nut and worm wheel 00 is turned, but of course to a much less extent. This also adjusts the position of the wheel slide 38. The compensating mechanism for automatically turning the II 2 in which shaft I21 responsive to trulng of the grinding I wheel 20, will be later described.

Referring now to Figures 4 and 5, the ball bearing Journal 00 includes a housing I30 which is a long sleeve extending to the left having a hollow cylindrical portion I3I integral with it. Siidable in the cylindrical portion I3I is a slotted sleeve I32 having slots I32 one hundred and eighty degrees apart. The right hand side of the sleeve I02 holds a ball thrust hearing I.

box plates I," and 'Iflfres'pectively m. and: [53.11am t-tur o; is vent escape-n1 fluid from th 's'houlderj Ill-"on thesieeve sl t ve insfn v s' s' cross shaft" I00 having an eccentric ;The shaft I56is'iou'rnalleti in an integral journal portion I51 formed in the hollowcylindrical portion I3I and in a journalibox lig ecured Theeccentric '6 cylindrical portion .IlI is a cylinder head I00 to which is secured a cylinder llito'thej-iother-end of which is secured a cylinder'head, I 42;

the cylinder l li lis afpiston to a sleeveill by meansof am is a shaft ts threaded fa eh shown'an'd havinga bolt head Iii-at. end. This shaft I Wis inethreaded .e'

right of'the {head 102;; fn m a'kin'g this adjust," ment the sleeve 'lli; ca be inde with a wrench and it" esira' V tions for 'this' purpose.

D portion I 56.

the hollow cylindrical portionlt portion I56 extends through a cylindrical hole in a guide block I60 which is slidable transversely (Figure 5) in a box IGI having a cylindrical outer surface that fits in the slotted sleeve I32. This box IBI has secured to the right hand side thereof, Figure 5, a cap I22 preventing the guide block I00 from moving in the box IGI in the direction of the axis of the shaft I50. The eccentricity of the portion I56 to the axis of the cross shaft I55 is very small (it may be about a, of an inch). It will now be seen that if fluid under pressure is introduced intothe left hand side of the cylinder III, the various parts including the screw shaft II will move to the right only as fast as permitted by rotation of the cross shaft I55 and eccentric portion I50. However, if a preliminary rapid infeed is wanted, the shaft I50 can be turned to move it to the left, whereupon the piston I45 can move to the right carrying with it the slotted sleeve I32 and the screw shaft 8| at a fast rate until the shaft I50 strikes the outside of the box IGI, after which further movement to the right will be only as fast as permitted by rotation of the eccentric portion I56.

Referring now to Figure 4, secured to the lower end of the shaft I55 is the hub I65 of a gear segment I60, as by means of a nut I61. This gear segment I06 is in engagement with rack teeth I60 formed on a long piston I10 in a cylinder "I which has a slot I12 therein to permit the teeth of the gear segment I66 to engage the rack teeth I60. Movement of the piston I10 in the cylinder "I thus rotates the eccentric I56. Therefore bycontrolled flow of fluid to the cylinder "I, as hereinafter explained, the fine feed at the end of a grinding operation is controlled.

Referring now to Figure 8, the large support has an'interior cylindrical surface I15 in which ilts'the exterior cylindrical surface of a cap I10 which is secured by bolts I11 to a portion of the regulating wheel housing 59. The

latter has an annular portion I10 which fits the outside of the round plate 68. It is thus that the housing 69 is mounted for adjustment about a horizontal axis on the support 08 and when Stumng th heads: 1

. th t-- v I agement with the sleeve land iti alsoin'threaded en' 'ga'gementj'with a head I52 secured to 3 the left hand e'nd of'thefslotted sleeve I22. By turning" the shaft- I 50 S thesepartanamely the piston I {5;- the sleeve"I40,i:the;shaftf'l i0,fthehead I52 and I the slottedsleeve I 32"," cari 'be' securely locked. to-x 7 the desired skew angle has been' attained, the bolts 81 can be tightened squeezing the annular portion I18 between a lip I18 on the plate 88 and the end of the support 88 thus clamping the parts together.

The housing 88 has a journal supporting extension I88 on the rear side and fastened to it is a journal supporting plate I8I on the front side. The extension I88 supports a ball bearing journal assembly generally indicated by the numeral I82 while the supporting plate I8I supports a ball bearing Journal assembly generally indicated by the numeral I83. These Journals I82 and I83 rotatably support a spindle I85 upon which is mounted the regulating wheel I8.

A feature of the invention is that the regulating wheel I8 can be adjusted along the axis of the spindle I85. A sleeve I88 has an enlarged cup-shaped portion I8'I which is threaded on the outside and also on the outside has a spline I88. A collar I88 is slidable over the threads and is keyed to the enlarged portion IN by means of 'a pin I88 fitting in the spline I88. A cup-shaped nut I8I fits on the enlarged portion I81 and can be turned by means of a. spanner wrench thus to adjust the position of the collar I88 and to tighten it against the regulating wheel 18.

The small end- I82 of the sleeve I88 is threaded at the end and also has a spline I83. A large collar I84 is slidable on the small'end I82 and has a pin I85 located in the spline I 83. The large collar I84 may be adjusted and tightened by a nut I88 located on the threaded small end I82 of the sleeve I88.

The sleeve I88 fits the spindle I85 and is keyed thereto by means of a key I8I. At one end of the sleeve I88 abuts a shoulder I 88 of the spindle I85 and the other end of the sleeve I88 is held in place by a nut 288 located on the threaded portion 28I of the spindle I85. It will be seen that the large collar I84 fit the counterbore 282 of the regulating wheel I8 while the collar I88 is thrust against the inside flat face of the counterbore 283 of the regulating wheel I8. In this manner the regulating wheel I8 is securely held on the spindle I85 and it may readily be adjusted in position axially of the spindle I85.

A multiple V-pulley 2I8 is keyed to the spindle I85 and is connected by a plurality of belts 2 to a multiple V-pulley 2I2 on the shaft of a variable speed hydraulic motor 2| 4. The construction of this motor will not be described herein because such construction iorms no part of my invention and the motor can be procured on the market. The motor 2I4 however is connected to pipes 2I8 and 2I'I and by regulating the flow of fluid through these pipes 2I8 and 2I'I the speed of the motor can be varied within wide limits and it can also be reversed. The hydraulic system of my invention together with a variable speed reversible hydraulic motor is very advantageous for driving the regulating wheel of a centerlss grinder. When a centerless grinder is grinding no actual power is required to rotate the regulating wheel, on the contrary what is really required is a brake. Nevertheless some means actually to rotate it is highly desirable to avoid starting inertia, so therefore some kind of a motor is indicated even though while grinding no actual power is required. On the other hand real power is required for truing and during the truing the regulating wheel should be rotated at a relatively high R. P. M. There should be many different low speeds for grinding and a high speed for truing. By using two fluid lines in parallel one having a throttle valve and the other having a check valve, I am able to provide a widely variable low speed drive for grinding with a high speed drive in reverse for truing.

The motor 214 is secured to a platform extension 228 of the regulating wheel housing 88 and so partakes of the skew adjustment 01' this housing. The casing of the motor 2 I4 has a base plate 22I which is secured by bolts 222 to another plate 223 which has long slots 224 through i with the axis of the work piece W. Since the regulating wheel housing 88 can and will be se cured to the swivel table 58 at various skew angles for various conditions of grinding, I make the truing apparatus adjustable to produce various hyperboloidal shapes. A plate 238 is secured by bolts 23I to the regulating wheel housing 88, the bolts 23l passing through slots 232 in the plate 238 in order to move the smallest diameter circle of the regulating wheel to either side of the center position axially to compensate for the position of the axis of the work piece above or below the plane of the axi of the grinding wheel and the center of the regulating wheel. Usually the work piece is slightly above this plane.

The plate 238 has a dovetail 238 which guides a slide 238 and having a dovetail recessed portion 231. The slide 238 further has flat portions 238 resting on the flat upper side of the plate 238. Thus the slide 238 can move parallel to the front of the machine and I can cause it to move at a. constant speed by means of a straight truing cam bar as the truing diamond is moved. thereby to give the truing diamond a straight line skew movement to generate the desired hyperboloidal shape for the regulating wheel 18. On the other hand, by this mechanism I can form a more complicated shape of the regulating wheel by a curved cam bar which may be desired to produce more accurate results for grinding large work pieces.

Referring now to Figures 11 and 12, the slide 238 has an upstanding portion 248 which is bored and ground to form a cylinder 2 in which fits a piston 242 that is slidable in the cylinder 2. This piston 242 has a piston rod 243 that extends through a cylinder head 244 and is secured to an arm 245 by means of nuts 248 on a threaded end 241. The arm 245 is fastened to a slide 258 which has a long dovetail recess 25I fitting over a dovetail 252 formed on the side of the upstanding portion 248. The slide 258 is thus moved perpendicularly to the front of the machine by movement of the piston 242 within the cylinder 24I.

On the front end of the upstanding portion 248 is a head 255 to the cylinder 24I to which is attached a valve casing 258 having an operating handle 25! for causing the piston 242 to move rearwardly and forwardly a desired. Extending into the cylinder head 255 which has ports and channels is an adjustable needle valve 288 by means of which the speed 01 the piston 242 may be regulated.

The slide 288 has integrally formed therewith 

